A Minnesota man remained jailed Friday as investigators tried to determine whether $1.8 million found in his car was linked to a multimillion-dollar bank robbery in Washington state.

William A. Kirkpatrick, 57, of Hovland, Minn., was stopped Nov. 10 for speeding on Interstate 80 near Lincoln. He initially identified himself as Donald E. Wilson.

A search of his rental car turned up four handguns, along with locksmith tools, masks and fake police badges. The $1.8 million included $100, $50 and $20 bills stuffed into two duffle bags in the trunk.

The FBI believes the money may be part of the loot taken in the Feb. 10 holdup of a Seattle-First National Bank branch in Lakewood, Wash., south of Tacoma. The crime was committed by the so-called “Trench Robbers,” named for the long trench coats they wear during holdups.

Authorities have not said how much was taken. News reports placed the figure at $4 million to $5 million.

“I don’t think I’m speaking out of school when I say that was one of the largest robberies in U.S. history,” said Roberta Burroughs, an FBI agent in Seattle.

The Trench Robbers have robbed banks in 16 states over 15 years, said Ray Lauer, another FBI agent in Seattle.

Kirkpatrick is “one lead out of many we are looking at with regards to this investigation,” Lauer said.

“It is a sure thing the Seafirst robbery was a Trench robbery,” he added. “It’s not a sure thing this guy is a Trench Robber.”

The bills found in the car have not been conclusively linked to the Lakewood bank, Lauer said.

Alan Everett, an assistant U.S. attorney in Lincoln, said Kirkpatrick was charged in an indictment Thursday with being a felon in possession of a handgun and possessing a handgun with an illegally altered serial registration number.

Kirkpatrick, identified in a criminal complaint as a convicted burglar, was being held on the weapons charges.

An FBI spokesman in Omaha, Larry Holmquist, said no bank robbery charges have been filed in the case and would not comment further on the investigation.

Kirkpatrick’s girlfriend, Myra Penney, 40, also of Hovland, Minn., was arrested last week when she tried to post bond for Kirkpatrick with $100,000 in cash.

Everett said Penney had been held for several days on initial charges of money laundering but she was released Thursday. When asked why Penney was released, Everett declined to comment.

A criminal complaint against Kirkpatrick - who was known to use several aliases - and Penney claims the couple spent or deposited large sums of money over the last four years, including $183,000 in cash for a Minnesota house.

According to the complaint, the Internal Revenue Service has no record of Kirkpatrick ever paying income tax and no record of Penney paying income tax since 1990.

The criminal complaint also said an informant told federal authorities in August 1996 that Penney had paid several Minnesota contractors in cash to build a log home on the north shore of Lake Superior.

She and a man identified as Charles Gehrs also opened an account at a Minnesota bank, where they deposited some $134,000 in cash, the complaint said.

The complaint also said Kirkpatrick and Penney rented a hotel room in Eagan, Minn., on Nov. 3, planning to stay through Nov. 14. Kirkpatrick then flew on Nov. 9 to Las Vegas, telling a travel agent he had rented a car to “pick something up and drive it back to Minnesota.”

Penney remained behind at the motel. Kirkpatrick was arrested in Nebraska the following day.

The complaint said on Nov. 14, four days after Kirkpatrick was apprehended, search warrants were executed on the Eagan hotel room and the Hovland home.

In the hotel room, agents recovered about $3,000 in cash, a loaded handgun and “various items of expensive jewelry and clothing,” the complaint said.

A stolen Social Security card, a stolen driver’s license and altered identification documents bearing Penney’s photo were found inside the home, the complaint said.

George Andrew, special agent in charge of the Omaha FBI office, said Kirkpatrick has told authorities “absolutely nothing” about the money.

Spokane Valley is poised for growth with a balanced budget, a new city hall building and infrastructure improvements to lure new businesses to the city, Spokane Valley Mayor Rod Higgins said at a State of the City address on Wednesday.